Dystonia is a disorder characterized by involuntary muscle contractions that cause slow repetitive movements, abnormal postures, or both. We had generated a novel Dystonin gene trap (DstGt) mice, in which actin-binding domain-containing isoforms are disrupted. Homozygous DstGt mice showed typical progressive neurological symptoms: severe motor disorders in their limbs and twisted postures. Electromyogram showed abnormal co-contractions of agonist and antagonist muscle in DstGt homozygotes. In histological analyses, abnormal neurofilament accumulation was observed in both peripheral and central nervous system. In order to know the abnormal neural regions possibly affecting the motor disorder in these mice, we mapped the distribution of abnormal neurofilament protein and found that it mainly concentrated in the motor-related neurons, suggesting that they are involved in the abnormal motor phenotype in DstGt.